A fixture fitting functions to freely change the length of a chain loop such as a necklace. The terms “chain” or “chain loop” are used herein broadly to refer to any thin flexible member that may be connected to its self to form a loop or ring. The fitting comprises an upper lid, a lower lid and a spring. The spring and the lower lid are housed into the upper lid. The upper lid and the lower lid are nipped between a person's fingers to compress the spring, the lower lid is moved downward, then the chain is inserted into a chain passing hole in the lower lid from a chain passing hole in the upper lid. On releasing fingers, the lower lid is biased in the nipping direction by the spring, and the chain passing hole of the upper lid and the chain passing hole of the lower lid sandwich the chain to fix the chain. See, for example, Japanese Utility Model No. 3089926.
There are other fittings which have a hollow housing including a pair of aperture portions, through which a chain or the like is inserted, on a side surface, an insert body built inside the housing slideably to abut to the chain inserted through the above described aperture portions with a head portion being held retractably on an interior surface of the hollow housing, and a spring for biasing the insert body in a direction to abut to the chain. These fittings are capable of freely changing the length of the chain ring. See for example, Japanese Patent Laid-open No. 2001-219.
There are fixture fittings capable of freely changing the length of a chain loop by providing opposing holes in a hollow outer body, into which is inserted an elastic body constructed of rubber, silicon rubber or the like having a through hole portion therein. By inserting a chain through the outer body and the elastic body, frictional resistance of the elastic body causes the chain to stop at an optional position. See for example, Japanese Patent No. 2971453.
However, the fittings disclosed in Japanese Utility Model No. 3089926 have structure for pressing the chain with the sidewalls of the upper lid and the lower lid. The fittings enclosed in Japanese Patent Laid-open No. 2001-219 have the disadvantage that the chain will bend at the aperture portions in the hollow housing when the chain is slid, because a pair of aperture portions included on the side surface of the hollow housing do not oppose each other due to the insert body, and since the chain slides in contact with the aperture portions, the chain doesn't move smoothly. The fitting disclosed in Japanese Patent No. 2971453 is used by sliding them frequently, the chain and the elastic body such as rubber, silicon rubber or the like will deteriorate due to abrasion, and in such a case it is difficult to repair them.